Muscle flexing commit; put the "any key modifier" to work, also exposed (ugly) in keymap editor. Notes for it works: - You can use any keyboard key to become modifier now (not mouse buttons) - But, if this key was assigned to be a regular hotkey, that still gets triggered, obviously. - So: only use unused keys for this, like "~" or other special ones? For test fun: L+K now does animplay.